1. Field of the Invention
The present invention relates to an earphone. More particularly, the present invention relates to an earphone which is used by placing it inside an ear.
2. Description of the Related Art
FIGS. 1 and 2 are schematic views illustrating a conventional earphone such as the one disclosed in Korean Laid-Open Patent Publication No. 10-1998-018579, which is hereby incorporated by reference in its entirety.
As illustrated in FIGS. 1 and 2, a conventional earphone 1 includes a cover connected to and combined with an earphone cord 5 at its lower part, an electroacoustic transducer 10 located inside the cover 4, a protection plate 2 combined with a front side of the cover 4 so that the electroacoustic transducer 10 is protected, and an ear piece 3 in a predetermined shape located outside the protection plate 2.
The electroacoustic transducer 10 for converting an audio signal to sound may be, for example, a moving coil type transducer. In this type of a transducer, a voice coil is wound around a bobbin 12, and the bobbin 12 is integrally attached to a diaphragm 11. The voice coil or diaphragm is inserted into a gap 14 in a magnetic circuit 13.
The protection plate 2 which opposes the diaphragm 11 is provided on a sound emanating side or front side of the transducer 10 and is made of a metal plate of substantially the same size as the diaphragm 11. The protection plate 2 has a number of holes 21 through to allow sound waves emitted from the diaphragm 11 to pass through.
The ear piece 3 covers the front side of the protection plate 2. The ear piece 3 is located within a listener's ear when the earphone 1 is worn. The ear piece 3 has a protruding portion 30 that fits into an entrance of the external auditory meatus (i.e., the ear canal). The protruding portion 30 is made of a material having an appropriate elasticity, such as rubber or plastic. The tip of the protruding portion 30 has a number of sound emanating holes 31.
The cover 4 covers a rear face of the transducer 10. The transducer 10 is connected to the earphone cord 5 through an introducing portion 40, which is located at a lower part of the cover 4. An air chamber 41 inside the cover 4 is open to the outside through a passage 42 of the introducing portion 40. The cover 4 is provided with a number of holes 43 which are closed by an acoustic resistant material 44.
An air chamber 32 is formed in front of the transducer 10 by the ear piece 3. The air chamber 32 is open to the outside through an opening 34 and a non-woven fabric 35 which are formed on the ear piece 3. The opening 34 is located to the side of the central portion of the ear piece 3 as shown in FIG. 2. Thus, when the earphone 1 is put in the ear E such that the protruding portion 30 is inserted into the ear canal or the external auditory meatus, the opening 34 is located in the cavum concha F, thereby covering the skin of the cavum concha F.
In the conventional earphone 1, the whole earphone 1 including the protection plate 30 and the cover 4 is inserted into and supported by the cavum concha F, and the introducing portion 40 of the cover 4 is introduced into and supported by the intertragic notch. If a user wears the earphone for a long time, the pressure on the anti-tragus H and the tragus G, or the contact with a protruding portion of a helix K may cause discomfort.
Furthermore, since the protruding portion 30 of the ear piece 3 is at the front of the transducer 10, when the earphone 1 is inserted into the external auditory meatus, the transducer 10 is almost horizontal with respect to the cavum concha F. Accordingly, the opening 34 and the nonwoven fabric 35 contact the cavum concha F. When the opening 34 of the ear piece 3 is blocked by the cavum concha F, low frequency sounds (i.e., bass sounds) generated by the transducer 10 cannot be transmitted. Furthermore, the opening 34 of the ear piece 3 is adjacent to the protection plate 2. Thus, there is only a small space created in the ear piece 3 where the opening 34 is provided, and bass sounds may be muted.
Accordingly, there is a need for an improved earphone for insertion into the ear canal that provides increased comfort and better sound quality.